Over the last five years much progress has been made in our understanding of the pathogenesis of Meniere's disease (MD) and the important role that disturbances of inner ear fluid homeostasis play in a variety of hearing and balance problems. Through studies of mouse models, a number of inner ear disorders affecting hearing have been identified that involve defects in genes that regulate ion channels and ion and fluid regulation; however, a bridge from these experimental studies to clinical studies is lacking. We are seeking NIH funds to support, in part, the Fifth International Symposium on Meniere's Disease and Inner Ear Homeostasis Disorders to be held April 2-5, 2005, at the Universal Hilton, Universal City, California. The expected number of attendees is 250-300 otolaryngologists, pediatricians, general practitioners, and basic scientists (cell biologists, immunologists, molecular biologists, epidemiologists, etc.) from around the world. The Symposium will consist of three Special Lectures on selected topics of importance, five Mini-Symposia, two Panel Discussions and contributed papers (oral and poster presentations). A discussion will follow each presentation. The aims of the Fifth International Symposium on Meniere's Disease and Inner Ear Homeostasis Disorders are: 1) to review new discoveries that have been made in basic and clinical research since the last International Symposium on Meniere's Disease and Inner Ear Homeostasis held in Paris, February, 1999; 2) to critically review recent discoveries in epidemiology, genetics, microbiology, immunology, cell and molecular biology, pathogenesis, prevention, diagnosis management and sequelae of MD; 3) to provide a scientific forum for basic and clinical scientists and physicians in order to enhance interaction and collaboration and to take advantage of new research opportunities; and 4) to widely disseminate information by publication.